Manufacture of artificial stone or brick and the preparation of lime therefor.



UNITED, STATES PATENT ()rnrcn.

V OSKAR HUGO ANDERSON, OF STOOKHOLM, SWEDEN, ASSIGNOR, BY MESNEASSIGNMENTS, TO SILIOATE BRICK SYNDICATE, OF MONTREAL, CANADA,

A OORPORATION OF DELAWARE.

MANUFACTURE OF ARTIFICIAL STONE R BRICK AND [HE PREPARATION OF LIMETHEREFOR.

. SPECIFICATION forming part of Letters Patent No. 702,611, dated J 111902- Applioation filed December 4, 1901. Serial No. 84,659. (Nospecimens.)

T0 at whom, it may concern:

Be it known that I, OSKAR HUco ANDER- SON, a subject of the King ofSweden and Norway, and a resident of Stockholm, Sweden,

have invented Improvements in the Manufacture of Artificial Stone orBrick and the Preparation of Lime-Therefor; and I do hereby declare thatthe following is a full, clear, and exact description of the same.

[o The invention relates to the manufacture of so-called silicate stoneand the simul taneous preparation of the lime used in its manufacture.

The object of the invention is to simplify and improve the process inthe following respects: First, dispensing with the introduction ofwater, low-pressure steam, or exhauststeam into the chamber in which thebrickhardening and lime-slaking operation is car- 20 riedon, and soavoiding all chance of excessive humidity during such operation; second,diminishing the quantity of lime required in the mixture of sand andlimeused.

In carrying out the improved process a mixture of about ninety-five percent. in weight of common sand and five per cent. of thoroughly slakedand dried lime, preferably also pulverized, is prepared and dry-mixedvery thoroughly, after which sufficient water is added to moisten themass, so that it can be molded into bricks or stones of any desiredform. The bricks thus prepared are hardened in the usual manner byinclosing same within a hardening chamber or cistern, but

subjecting them to the action of high-pressure steam only-c. e., steamat not less than one hundred pounds per square inch--thus keeping thechamber at all times free from excessive humidity instead of introducinga 0 quantity of water, low-pressure steam, or exhaust-steam, (resultingin an excess of moisture,) as has been the practice hitherto. The use ofhigh-pressure steam only enables the customary simultaneous slaking (inthe same chamber) of the lime used in the preparation of the brickmixture to be properly effected and with better resultsthan heretofore.For

instance, it has been ascertained by experiment that for the slaking ofa quantity of lime corresponding with the five per cent. in the brickmixture sufficient moisture in vaporized form can (by the action of thesteam resolving the sand and lime into silicate and Water and releasingthe free moisture taken into the chamber by the bricks) be derived fromthe bricks which are being hardened to thoroughly slake the lime locatedin the same chamber, but separate from such bricks, and consequently allnecessity for introducing a special additional supply of water,low-pressure steam, or exhaust-steam, as heretofore, is avoided, withresulting simplification of the process and the removal of all chance ofexcessive humidity. Furthermore, thevaporized moisture produced is bythe high pressure of the steam caused to permeate the unslaked lime soeffectively that the lime is reduced to the finest pulverulent form. Thechamber beingfree from excessive humidity from start to finish of thehardening operation is a distinctively novel feature of my process andcontributes in a large measure to the improved product thereof in thatthe molded article is at no time while in the chamber liable by anexcess of moisture to collapse, crack, or otherwise lose its'originalclosely-pressed condi tion and form, and again, from-the absence of anyexcess of moisture it results that the slaked lime being drier than itotherwise A would be naturally assumes a finer pulveru- 8o lent form,and as a consequence every portion unites effectively in the subsequentsilicate formation of the brick mixture.

It is desirable Where a much superior qualityof brick is to be producedto continue the application of the steam for a short period beyond thetime'when the hardening of the bricks has been effected and -the limeslaked in order to bring about even a finer pulverulent condition of thelime by such excessive 9o drying, and, further, the lime after removalfrom the'hardening-chamber may, if desired, be subjected to the actionof any suitable pulverizer in order to grind as finely as possible allforeign substances which may have re- 5 sisted the action of the steamor the dried lime be passed through a separator to free it from suchforeign matters.

As an alternative for the continuation of the application of-thehigh-pressure steam beyond the time required to slake the lime (as justmentioned) superheated steam may be employed instead of suchcontinuation of the high-pressure steam to produce the same result inmuch less time and with a quicker setting or hardening of the bricks.

In order to obtain a harder material for the manufacture of silicatestone, the lime after being slaked in the manner mentioned is mixed witha certain percentage of sand and heated to redness. The mixture thusprepared then takes the place of the lime in the brick mixture, and inthis case the mass is moistened with diluted hydrochloric acid insteadof water before being pressed and treated with steam.

I am aware that the process of slaking lime in the same chamber with thebricks to be hardened has been heretofore known, such slaking beingeffected by the Water of condensation falling upon it, and I am alsoaware, as above indicated, of the treatment of compositionsincludingsand and lime by the application during the hardening process oflowpressure or exhaust steam followed by highpressure steam; but I amunaware that it has ever been ascertained prior to my invention thathigh-pressure steam alone is sufficient and effective to act on thebricks in the chamher to vaporize the moisture therein, force suchvaporized moisture without water of condensation through the unslakedlime most effectively, and harden the bricks, the chamher beingthroughout the operation quite free from excessive humidity.

What I claim is as follows:

1. The process of simultaneously making brick or other articles out oflime and sand and slaking lime, the same consisting in mixing the sandand lime with the minimum amount of moisture necessary to hold themixture in form, next molding the mixture into the desired shape,inclosing the molded articles in a chamber together with a separatequantity of unslakedlime, and finallyhardening the bricks, and slakingthe lime by the application of high-pressure steam only, substantiallyas described.

2. The process of simultaneously making brick or other articles out oflime and sand and slaking lime, the same consisting in mixing the sandand dry-slaked lime in substantially the proportions specified,moistening the mixture with the minimum amount of moisture necessary tohold it in form, next molding the mixture, inclosiug the molded articlesin a chamber together with a quantity of unslaked lime approximatelyequal to that contained in the batch of articles to be hardened, andfinally hardening the bricks and slaking the lime by the application ofhighpressure steam only, the chamber being free from excessive humiditythroughout the operation, substantially as described.

3. The process of making brick or other articles out of lime and sand,the same consisting in mixing substantially ninety-five parts by weightof silicious sand with five parts by weight of dry andfinely-dividedlime and with the minimum amount of moisture necessary tohold the mixture in form, next molding the mixture into the desiredshape, inclosiug the molded articles in a chamber, together with aquantity of unslaked lime approximately equal to that contained in thebatch of articles to be hardened, and finally hardening the mixture andslaking the lime by the application of dry steam only at a pressure ofnot less than one hundred pounds to the square inch, the chamber beingfree from excessive humidity throughout the operation, substantially asdescribed.

4. In the manufacture of silicate stone or bricks and the preparation oflime required therefor, first mixing a quantity of sand with a mixture,previously heated to redness, of sand and slaked lime, moistening themass with diluted hydrochloric acid, pressing same into brick form,placing the bricks in a chamber and also placing in the same chamber,but separate from said bricks, a quantity of lime to be slaked, closingsaid chamber and introducing thereto high-pressure steam, wherebyvaporized moisture will be derived from said bricks and caused tothoroughly permeate the separate quantity of lime to be slaked, as setforth.

In testimony whereof I have affixed my signature in presence of twowitnesses.

OSKAR HUGO ANDERSON.

\Vitnesses:

FRED J. SEARS, ARTHUR IT. EVANS.

